Enhancing the Formation of C2+ Hydrocarbons in CO2 Hydrogenation Through Co2C/CeOx Interactions.

Abstract

Cobalt carbide (Co2C) shows promise for CO2 hydrogenation to C2+ hydrocarbons via the CO2-Fischer-Tropsch pathway, although the production rate is still limited by the slow CO hydrogenation step. Herein, we developed CeOx-modified Co2C catalysts. At a Co/Ce molar ratio of 99, the catalyst achieved a C2+ hydrocarbon space-time yield of 106 mmol gcat -1 h-1 at 35% CO2 conversion (300°C, 3 MPa), outperforming all reported Co-based catalysts and comparable to some Fe-based catalysts. Characterizations and kinetic studies reveal that highly dispersed CeOx interacts with Co, forming abundant and intimately contacted interfaces and effectively tuning the electronic structure of Co2C. The Co2C-CeOx electronic interaction enhances CO adsorption and H2 activation, accelerating the rate-determining CO hydrogenation and ultimately boosting C2+ hydrocarbon formation. This work provides a feasible strategy for designing efficient Co2C-based catalysts for CO2 hydrogenation.